Patients could have to wait up to 10 weeks for a review of scans at University Hospital Kerry to be completed.
46-thousand cat scans, X-rays and ultra sounds are being re-examined after 3 misdiagnoses.
The tests are being traced back to a single worker between March 2016 and July of this year.
A helpline will open at 9am on 1800-742-900.
Kerry TD John Brassil has called for a review around mechanisms at the hospital.
18,000 files have already been reviewed resulting in 21 patients being called back for “repeat imaging”.
None required any further follow up or treatment.
A dedicated information line has been established at UHK – patients who have concerns can contact 1800 742 900 – this number will operate from 9am to 5pm Monday to Friday.